Spring suspension for motor vehicles



Aug. 19, 1952 Filed Dec. 28, 1946 W. D- ALLISON SPRING SUSPENSION FOR MOTOR VEHICLES '7 Sheets-Sheet 1 g- 19, 1952 w. D. ALLISON 2,607,610

SPRING SUSPENSION FOR MOTOR VEHICLES Filed Dec. 28, 1946' '7 Sheets-Sheet 2 "X INVENTOR.

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' SPRING SUSPENSION FOR MOTOR vsurguzs Filed Dec. 28, 1946 7 Sheets-Sheet 4- I INVENTOR. I

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Aug. 19, 1952 Filed Dec. 28, 1946 Aug. 19, 1952 w. D. ALLISON 2,6075610 SPRING SUSPENSION FOR MOTOR VEHICLES Filed Dec. 28, 1946 7 Sfleets-Sheet '7 ill!! INVENTOR- n lzzl dlrzj/qlllzsa/z v mim Patented Aug. 19, ,1952

UNITED STATES PATENT OFFICE 2,60%,610 7 4 I SPRING SUSPENSION Foit Moron p VEHICLES I William D. Allison, Detroit, Mich; Application December 28, 1946, Serial No. 719,038

This inventionrelates to motor vehicles and particularly to improvements in the spring'sus-.

pensions therefor. The invention is applicable to various types of motor vehicles such as automobiles of the pleasure or passenger types, busses, trucks, ambulances and commercial vehicles. For the purposes of illustration the invention has been shown herein as embodied in a motor vehicle having a chassis adapted to be utilized in a pas-. senger or pleasure type automobile.

One of the principal objects of the present in-' vention is to provide a spring suspension'for a motor vehicle capable of improving the riding characteristics of the vehicle, increasing the.

cheap car to be produced which will have riding characteristics superior to those-of conventional automobiles and which will enable the frame or body of the car to be maintained substantially level regardless of varying load conditions. the important advantage of materially reducing or=largely eliminating pitchingand tossing ofthe vehicle and of greatly reducing body shake and vibration when the vehicle is travelling over rough roads. I

Another object of the invention is to provide what may be termed a-balanced spring suspension, preferably a torsional or torsion bar suspension common to the front and rear wheels of the vehicle at each side thereof, said suspension enabling much softer or lower rate springs to be utilized and being supplemented by spring means, preferably of the torsional kind, effective to vary the spring resistance at one end of the frame relative to the opposite end, means being PTO? vided for deflecting such spring means to com pensate for relative changes in elevation of opposite ends of the frame. due to variations in static load thereon. As a result of this feature of the invention it is possible to maintain the average effective riding height of the vehicle body substantially constant within the range of the load capacity of the springs regardless of whether the vehicle is empty or whether varying loads are carried. thereby.

The present, spring suspension also has 35Claims. (Cl.280'104) In accordance with the embodiment of the 'invention,'her'ein illustrated by way of example,

there is provided longitudinal torsional or torsion bar spring means connecting through the me dium of front and rear lever arm means a pair of 'front and rear wheels at each side of the vehicle. The construction is such that the lever arm means for each front and-rear wheel will torsionally deflect the spring means in opposed directions upon displacement of the wheels in corresponding vertical directions. Thus, when a front or rear wheebpa'sses over a change in elevation, producing a raising or lowering effort at one end of the 'vehicle, a simultaneous and similar raising or lowering effort is. applied at the opposite end of the vehicle. The action of the spring suspension, therefore, results in the simultaneous application of substantially equivalent vertical forces at opposite ends of the frame or body whenever the wheel or wheels at one endof the vehicle pass over a change in elevation. As a consequence, the ,vehicle rides substantially free of pitchingwandside sway. By thus providing springmeanscommon to the front and rear wheels the 'suspension is what may be termed rear. of the frame. For example, the additionof passengers or baggage at the rear will lower the elevation of the rear of the frame and body and raise or elevatethe front end. In accordance with the invention additional compensating spring means, preferably of the torsionalor torsion bar kind,,is provided-at the rear or the front of the vehicle, or at both ends, for varying the spring resistance at one end ,of the vehicle rela-.

tive to the opposite end. In addition, means is provided, such as power operated'means, for independently deflecting the compensating spring means so as'tocompensate for relative changes in elevation of opposite ends of the frame and thereby levelize, or substantially so,, the frame and cause the vehicle to ride substantially levelor at an'even keel. v 7

Other objects of this invention will appear'in the following description and appended claims, reference being had to the accompanying draw 3 ings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a fragmentary plan view, partly in section, of a motor vehicle chassis provided with,

a spring suspension constructed inaccordance with one embodiment of the present invention.

Fig. 2 is a side elevation of the structure shown in Fig. 1. p I:

Fig. 3'is a vertical section taken-substantially through line 33 of Fig. 2 looking in the direction of the arrows.

Fig. 4 is a vertical section takensubstantially through lines 4-4 of Fig. 2 looking in the dir'ec tion of the arrows.

Fig. 5 is an enlarged detail View illustrating the connection of the torsionbarsatthe. rear end of the vehicle.

. 4; I V invention as applied to a vehicle or automobile having pairs of front and rear wheels and a load carrying frame supported thereon through the medium of a spring suspension embodying the present invention. In the interest of clarity the vehicle superstructure or body, the power plant and power train have been omitted from the drawings. Although the front and rear wheels are shown; as independently mounted through the'medium-of pairs of swinging suspension arms I it will be understood thatjother types of wheel Fig. 6 is a view in elevation of the rear-wheel spring mechanism taken from the rear side thereof.

Fig. -.7 isan enlarged section taken substantially. through lines *l- -l-of Fig. '1 -looking in the direction'of. the arrows. I

Fig.8- is an enlarged plan view. partlyiin-sc- H-*-H1Dff Fig.: '10: looking the" direction of. the

arrows. 1

' Fig.1-l2'is aj fragmentary-plan view of the front end of ;a' vehicle, this view 'being similar in'zpart tosFig. la'but. illustrating a: further modified con- Fig. 17 is an'enlarged-'section'taken substan-* the 'di're'ction 'of the arrows.

".Fig. 8 is a view inpart' similar'to' Fig. 16 but" illustratingfafurtherm difi a V V "Fig. 19 is an enlarged section taken Sllbsth;

-supports may be utilized without departing from thefbroader ;aspects of the invention.

espect, therefore, the rear wheels or front wheels may be supported for vertical movement through the medium'of any conventional types'oi axle means or supporting arms.

As illustrated in the drawings, the chassis or bodyfrarne is shown, by way of example, as comprising spaced longitudinal side sills or frame members: 22) rigidly connected together by means of -amZinIfdIOpYtYDBifIOHtLOIOSS' member 2 l and'a main: Ldrop type rear: cross member 22. Adjacentthe rear of the vehicle the" framesillsare also :rigidly connected togetherby means of; a torque-arm supporting :cross'imember 23, andin advanceyof'ithe front cro'ssxmember 21 there; is provideda cross memberz i rigidly sec'uredto the frame. sills. The front and rear wheel of the vehicle arexindicated-tatrgn and'Zii respec Asiillustrated :in'Figs. l to .3'-'inclusive,: each front :wheeliZS istsup'portedaby upper and lower short and long suspension arms "21 and528, each 'being-oiwish-bone construction. The upper and lower suspension or lever armslt and 28 are mounted at right-angles to the longitudinal axis of the-vehicle for-swinging movement in a substantially vertical plane and are joined together at their outer ends by a spindle and king pin mounting 29 of 'any' s'ui'table type. T The inner bifurcated r ends of each upper sus gien sion' arm Z? carries a tubular member 39 extending through aligned apertures in the ends 'of the arm and welded 'thereto. Each tubularsection is jour nalled in-a bracket-e1 rigidly-secured to the cross member 21- and is provided with 'asquare socket, asillustrated ih Fig. '3, withinwhiclr is hired the square end SZapfa forwardly extending torsion barf "32. Each' torsion bar iii' terminates at its front} ana m a square portion fixed Within-a square socket-in a front- 'rno'unting'i memberf33 rigidly secured to oneend of the'cross' member 2 6.

tially 'throu'ghlinesi9-49 of- Figv18 no ng v the :lirection of 'the arrows. I v

F igs. 2O and 21"arevi ew'slin part *simil'ar'to Fig.; '16" but illustrating further modifications,

Before explaining in 'detail the present inven tion it is to be 'un'derstoed that theIinvention'is' not "limited in its application to the. details of 1 construction and arrangement of parts illustratedin theaccompanying drawings, since the invention is capable of other, embodiments and of beingpracticed or carriedout .in various ways. Alsojitis' to be unde'rstoodthatv the phraseology orf terminology employed herein is. for the .purposevof description and not of. limitation.

This application .is'. a continuationeinepart of my application Serial No. 665,192, filedApril .26;

of examplacertain embodiments. of jthe present The' construction is preferably such that the socket'memben'to which the forward end of the torsion bar 32 is attached, is adjustable angu" larly to adjust 'thetorsion bar to the desired initi'ahtorsion in either direction and thereafter locked inpositionf, V p

From the'forego'ing construction it will be seen that-{a front end stabilizing 01;" height adjusting torsior'i barf eg i's fc'fonnected atits rearend tothe inner endoffea ch' upper spring suspension arm Zflfand isfrig'idly corin ected lat .its forward'end totheframe cross member E l; Accordingly, up.

and' 'down' swinging" motion of the suspension arm's. 2'1' about ljthe longitudinal aXesof thetu; bular membersffiil will torsionally twist .or defleet the torsion bars. 32 which, as arconsequenc e,

I v will yielding-1y resist. up-and down movement of thefrohtQWheels 25 one independently of the other. iTheouter end of each upper suspension arm 2'! is pivotal-1y connected at 3 to a king mounting 35, the latter permitting the frontwheel to In this turesi: in the ended the arm and-"iswelded v thereto. Each' tubular. member 36 is 'journalled in: depending brackets 31 riveted" to the frame cross" member 2| and is providedinteriorly with a square socket 38 within which is fixed-the square'e'n'd 39a of a main torsion bar spring 39.

The. connection between the -f'ront end of the torsioniba'r 39 and the inner bifurcated ends 'of the .lower suspension arm '28 -is more particularly illustrated in Fig. 8. f v r The outer end of each lower's'uspension arm 28 is pivoted at 40 to the lower end of the spin dle 'support29 at the locality of the lower king pin-mounting 4|-, this construction permitting steering motion of thefrontwheel 25 While enabli'ngthe lower suspension-arm 28 to swingin a vertical plane consequent to' up and down movement of the wheel. The pivotal connections between'the inner and outer ends of the upper and lower front suspension arms preferably include rubber or' flexible bearings as in my above identified application,'iiled April 26, 1946. I

Steering control is provided at the front wheels 25 through the spindle and king pin mountings or supports 2-9 by steering mechanism, generally indicated at arrangedand mounted in front of the suspensionarms 21, 28 and the cross frame member 2|." This steering mechanism comprises a drag link 42a, tie rods 42!), 'steering arins 42c connected-to the members 29, an idler arm 42d, a steering gear Pitman arm 42, "and associated joints, bearings and mountings including a steering 'column42f. I I v f d the present embodiment' of the invention thr'ear'wheels 26'are each supported for independent vertical movement by means of upper and lower swinging suspension arms 'or levers 43 and 44'. The inner end of each upper suspension arm 43 is pivoted at 45 through 'the medium ofla flexible'or rubber bearingjo'r bush irig to a bracket "46 rigidly secured'to the frame member 22. This frame member, as illustrated in Fig'. '1,-is-i 'n the present instance composedof two" longitudinally spaced vertical plates 22a and 22b between which each bracket 46 extends. These plates 22a and 22b are centrally formed to receive the differential housing and are rigidly joined together along their top edges by means offa'tie plate 22c. Each upper suspension arm 43 is in the'form of a bell crank lever'provided at its innerend with a verticallyand downwardly extending crank arm 43a pivoted at its lower end at 41 through the medium of a flexible or rubber. bearing or bushing to the outer end of a tension link'48. Each link extends outwardly between the plates 22a, 22b of the cross frame member Hand is pivoted at its inner end'at 49 through the medium of a flexible or rubber bearing or' bushing to ,the upper end of a lever arm 50 also interposed between the. frame plates 22a, 22b. Passing through the lower 'end of each lever arm 50 and rigidly secured thereto is a tubular member. 51 journalled in the cross frame member 22 and provided with a longitudinally extending squaresocket 52 within which is fixed the rear square end 391) of one of the longitudinally extending main torsion bar springs 39.

From the foregoing construction it will be-seen that the forward end of each main'torsi'on ba'r' spring 39 is rigidly anchored to the inner endof one of the front'lower suspension arms fl and the rear end is rigidly anchored to the lower end of one of the swinging lever armsj5ll."

The outer end of each upper'suspens'ion arin 43 is pivoted at 53 through the medium era 'flex-ible or'rubber bearing or bushing to the upper end of arear wheel support and spindle mem ber 54 Each lower suspension arm-44 is pivoted at its outer end at 55 to the lower'end of'the wheel'support 54 through the medium of a fiexi"-' ble or rubber bearing or bushing. 'Sin'iilarlyjthe' inner end of each lower suspension arm 44 is 'secured to a tubular member 56 which is'iournalled in the plates 22a, 22b through the medium of'a flexible or' rubber bearing or bushing. if j It will be apparent from the foregoing' that on verticaldisplacement of either rear wlieeljii the lateral control exercised by the bellf cr ank 43 and connecting arm 44 is comparable Lt exercised by the front upper 'andlowerffsuspen' sion arms 21 and 28 on the-front wheelsyjflItwill' also'be apparent that all of the wheels of the ve-"I hicle will be independently sprung and each pair of front and rear wheels at each side oflthfe chassis. frame will be springably connected' in' common through the medium of one of the main torsion bar springs 39 which connects. the lower suspension. arm for the front wheel with the upper suspension arm forithe rear wheel, the. latter connection being accomplished through the medium of leverarm' 50, tension link 48.

bell crank lever 43'. g e

Referring'particularly, to Figs. 1 and 2, the rear wheels are controlled by means, of parallel. longitudinally extending torque arms 51 mounted to swing in vertical planesi Each torque arm isrigidly attached at its rear end to oneof-lthe rear' Wheel and spindle support members 54. The forward end of each'torque arm 51 is pivotally connected at 58 to a bracket 59 rigidly securedtof oneend of the cross frame member 23', the pivotal conne'ction'at 58 ,being accomplished through the medium of a flexible, or rubber bearingjor bush- 1' ing. The pivotal connections 58 between t e torque. armsand the brackets 59 provide acorn}-- mon transverse axis of swinging of the :tjorq'u'ei arms. .These pivotal connections 58 constitute fulcrum .points about which thearms swing'jin verticalplanes consequent to up and down {move-Y erits of the rear wheels and it will. be" noted that these fulcrum points are located above as well as forward of the axes 60 of therearwheelsl" The transverse horizontalaxis through thepivot or fulcrum points 58 preferably lies in a common plane intersecting both the common axes of the rear Wheels and the center of gravity, oftheaver age vehicle weight. The elevated positions of thetorque arm pivots 58 above, the centers of the. wheels'are particularly desirable for vehicles having .power applied through the frearqwheeis and eliminate thebackward pitclrofthevehicle on acceleration by. applyingv a vertical 'r rcei as well as a forward thrust to. the vehicle; name The net result on acceleration is for. both ends.

of the vehicle frametobe slightly elevated with-Q outv pitching. The lifting force-applied onfacceleration .through the torquearms 51 at the rear of the vehicle compensates for. the shift of weight, from front to .rear wheels and relieves.the.,rearl spring assembly from carrying this additional weight. On brake application in a vehicle ov-1.

ing in aforward direction a downward thrust is exerted .on the 'frameby the torque "aarms "51 through the torque arm mountings on cross 'framegmember 23. I

.In the present, embodiment the torsion bars-39, which constitute the normal springing means for the vehicle,are supplementedby a torsion bar 6! l at: eachvside of the vehicle for the purpose of additionallyspringingthe rear wheels and pro-5 viding smeans for; compensating for varying loads. These. torsion -bars-6I,=as;in the case'ofv springr resistanceat the rear of the vehicle so asto-compensatefor relative changes in elevation 'ofsthefront and-rear ends of the vehicle and thereby maintain the vehicle at asubstantially.

constant average riding height, The load compensating bars Glare shown-in the present embodiment for. the rearend of the vehicle only since.,in,present-day automobilesmost of the;

additional passenger and baggage loads are concentrated at the rear. However, it will be understood' thatl where. loads are distributed substan-,

tially evenly to the-front-and rear wheels these bars may be duplicated. for the front wheels and. operated in the same manner as hereinafter cle-v scribed. I

, :Each" load compensating barfil is provided at.

its rear endwith a flat sided or rectangular portion"6 l.afitting snugly within the. square socket 521against the, flat sided end 392) of thebar '39,, see Fig.5.. Fromlthis construction. it will be} apparent thatswinging movement of the lever arm resulting in turning of the tubular mem ber 5| will impart corresponding turning movement tozthe ends 391) andtla of each pair of torsiongbars'39 and 6|.

",Thelfront end'of. each load compensating bar SjLsee'Figs 2, andl, has a squared orqflat. sided portionffilb anchored within a correspondingly shaped socket in a tubular member 62 journalled in: apair of spaced depending angle brackets 6 3 riveted to the bottom flange of the chassis frame.

memberZU. Fastened tothe tubulerv inember621 and disposed. between therbrackets 63 is a worm geaf'fitmeshing witha worm 65 secured to a cross "shaft; 66. This shaft, as shown in Figsri andjflgextends transversely of the vehicle frame andlhasa worm 65 secured to each endthereof,

each'vvorm meshing with a worm gear 64. The,

'shaftfis'isijournalled at opposite ends in angle bracketsL6Tand-68 rivetedito the chassis frame members'zfl. Oneend of the shaft 66 projects beyond the associated bracket 61. and is driven byarelatively small reversibleelectric motor 69 supported by a bracket '10. The electric. motor 69 'is automatically actuated in response to changes in static load on-the rear 'ofjthe vehicle by 'a'switch, mechanism and wiring circuits, not

show'nherein, but fully shown and described in my cjopen ding application Serial No. 757,579,

filed June 2'7, 1947.;Provision is thus made for} operatingthe load compensating motor 69 in one direction'orthe otherin order to increase or changesor'by vertical motion" of the rear wheels during travel of the vehicle. The load'compen sating controls for the motor 69,'as shown and described in my said copending application,,will

only operate after a predetermined delay or in V terval of time; as it is only desirable that this 8 occur" whenzthe' pay load of the vehiclez-isrincreased or decreased :over. a relatively long :period of time.- V When the static load at the rear end ofthe vehicle is increased, asforexample by the -addition of passengers, the, motor 69 will be actuated. to :drive the "shaft'wfifi inone direction, thereby simultaneouslydrivingthe worm gears 64 in oppo- SitBsdilGCtiOIlS and, asa consequence, imparting antangular twist to; the squared endsrfilb ofithe torsion bars'fil. This will increase the torsional.

, deflection and;hence the spring resistance of the torsion bars '6 I tea-point necessary to compensate for the additional load, and'when the proper load compensation has .beenzreachedthe, motor 69 will I bedisconnected and the spring bars bl will .:be maintained in their conditionof,increased-"tor sionalxdeflection. -The reverse operation :will occur when-- the .payyload at the rear end of:;the vehicle is decreased, resulting in the, operation or? the motor 69 to unwind or decrease the torsional deflection of the springbarscfil. H

-When the vehicle is empty orwithout pay load, the main-torsional bars 39. preferably function to maintain or support the vehicle ata given-average or normal riding height, and in such ;case,the, compensating torsionbarslil. will be. initially placedu-nder very little or practically no torsion or twist. Under such conditions the fullest possible torsional resistance of the.bars-.9l,'through operation of the load compensating -motor :69, maybe-added to the torsion bars 39 in order to compensatefor varying increases inthe payer static load atthe rear of the vehicle. Ifhus, it is possible for the. present vehicle springsuspension to accommodate a pay or: static load at least equaltothesprung :weight of the vehicle while main-- taining! a substantially constant average ridin height and a fully normal axle'to frame clearance under no-load and full-load conditions. aExtremely soft springs may thus be utilized since under no conditions is it necessary to utilize springswhich are heavier than necessary to'carry: thesprung loads regardless of Whether. the vehicle is empty or fully loaded. For'example, the effective average spring'rate, utilizingthespring suspension of the present invention, canbe as low as approximately thirty pounds perinch per wheel as compared with conventional spring suspenw sions, utilizing either leaf or coil springs or a combination thereof, necessitating spring rates as high as one hundredand ten pounds-per inch per wheel.

The main torsion bars 39 may-be suitably.

guided and supported intermediate their ends is a depending an le bracket 12 having an ,apere ture to receive'a rubber bushing ll through which .the torsion bar 39 extends. bushing'permits torsional twisting or deflection of the-bar 39 hile also damping out vibrations thereof.

The: rubber lever 21. The bar extends through a torsion tube and is provided at itsforward end with a flat sided or squared portion Mb anchored within a correspondingly shaped sleeve "amounted within and rigidly'se'cured to the front end of the tube 15. The rear end of this tube is flanged-and bolted at the locality of these flanges at 16 to the cross frame member 2 I. From this construction it will be readily seen :that up and .down

deflect these tubes with the reaction effort of the tubes taken by the cross frame'member 2|. By thus utilizing the combined torsional resistance of the torsion. bar 14 and torsion tube 15 it will be seen that the bar 14 may be considerably foreshortened and, in fact, may be approximately one-half as long as would. otherwise be necessary in order to provide any given' torsional resistance for the front end stabilizing or height adjusting bars. 1

.In each of the embodiments hereinbefore de scribed the height adjusting bars or elevation stabilizers 32 and I4, 15 for the front end of the frame or car are introduced into the spring suspension for the purpose of assuring average nor- -mal riding height for'the front of the vehicle.

Since extremely soft spring ratesarepossible at the front and rear wheels with the present torsion bar suspension, I have found it desirable to install the additional springing at the front wheels in order to maintain anormal average riding height of the'front end under conditions such as when the front end tends to dip after a rapid or severe brake application or when the front end. tends to raise or elevateexcessively during rapid acceleration ofthe vehicle.- The elevation stabilizer bars 32 or l4, 15 under normal conditions may be in unstressed condition, i. e. free of substantial torsional deflection, whereas the main torsion bars 39 will be normally deflected or twisted an amountsuflicient to support the vehicle at the average riding height under noload conditions.- The stabilizer bars would; therefore, be twisted in-one direction or the other throughout action of the suspension arms 21 to resist elevation or lowering of the front end,- as a result of rapid acceleration of the vehicle or sudden application of the brakes, andwill tend to 'main'tain the desired average riding height at the front end.

-These stabilizer torsion bars may, if desired, be utilized in addition for load compensating purposes in' the same manner as the torsion bars 6| where it is desired, due to the construction of the vehicle, to compensate for substantial changes in the'pay load or static load at the frontend. In such instance the torsion bars 32 or l4 may be extended a suitableldistarice rea'rwardly of the cross frame member 2| and drivingly connected together for load compensating purposes-by a .one' of the frame members 28. Fastened to each same manner as illustrated in Fig. 5.

struction shown in Figs. 10 and 11 may be particularly adapted to vehicles, such as buses and trucks, where the load is more :nearly equally distributed over thefront and rear wheels, and of course it will be apparent that this mechanism adapted for any vehicle where substantial'increases or decreases in load occur at'lboth ends of the vehicle. x .1

1 Each front wheel 25 inthe embodiment of Figs. 10 and 1-1 is provided with a main torsion bar spring which at its front end is anchored to the inner end of the lower suspension arm or lever 28 at the axis of turning thereof in the same'manner as \previously described and as particularly shown in Fig. 5. Each such torsion :bar 80 has a square or flat sided rear end which is anchored within a correspondingly shaped socket in a bracket 8| fixed to one of the frame members 20.' Thus, up and down swinging motion of the suspension arms 28 will independently torsionallytwist or deflect the torsion bars 80. Each rear wheel 26 is also provided with a springtorsion bar 82 which is anchored in the same manner as previously described, and as particularly shownin Figs. 4 and 5, to the lower end of the swinging lever 50 at the axis of turning thereof. The front end of each'torsion bar 82 is provided with a squared or flat sided portion which is anchored within a socket fixed within a bracket 83 secured to one of the frame members 20. Thus, up and down swinging motion of the rear suspension arms 43 will torsionally deflect or twist the bars 82. a

In addition to the independent spring suspension bars 80 and 82 for the front and rear wheels,

I provide, in the embodiment of Figs. l0'and 11,

a load compensating spring suspension bar 84 for each front wheel and a load compensating spring suspensionbar 85 for each rear wheel. The bars 84 have their front ends squared or flattened and anchored to the inner ends of the suspension arms 28 at the :axis of turning thereof in the In like manner, each of the compensating b-ars'85 have their rear ends squared or flattened and anchored to the lower ends of the levers 50 at the axes of turning thereof in the same manner as illustrated in Fig. 5. The rear end of each-bar 84 is anchored within a tubular sleeve 86 journalled within depending brackets 81 secured to tubular sleeve 86 is a worm gear 88 driven by a worm 89 fastened to one end of a cross shaft 90 journalled .at op-posite ends in brackets secured to the frame member 20. The shaft 90 is driven by. aiload compensatin reversible electric motor .91. inthe same manner as previously described and :as particularly shown in Fig. '7.

- The front end' 'of each load compensating torsion bar-85 is anchored within a-tubular sleeve 92- journalled' within brackets 94 secured to one of the frame members 20. Fastened to each sleeve -92 is aworin' gear- 93 driven by a worm 95 secured'to one endbf a cross shaft" 96journalled at opposite ends-in brackets carried by the frame members 20. The shaft96 is operated by means of a load compensating motor 9'! in the "same manner sis-previously described and as particularly shown' in Fig. 7; I

The.'operation of the load compensating torsion bars 84 and 85 is substantially the same as above described. The pair of fro-ntstabilizer lbars 84 are controlled-to compensate for variations in loadat'the front of the vehicle by the motor 9| which is automatically operated, similarly to the aeone ao 7 .111 V --motor E9, to increase or decrease the twist or deflection-of these .bars to compensate for increases or-;decreases in leads at the frontend of the vehicle. Similarlyjthe motor 91 'is' automatically operated toincrease or decrease the twist 'or -cleflection of the torsion bars 85 in order to compensate for increases ordecreases in-loads at the rear end of the vehicle.

The embodiment of Figs. I a'nd 11 thus provides' independent torsion-bar springing 8B and "82 foreach' of the front andrear wheels to- 'vgether with load compensating torsion bar spring mechanism-'8 -and 85 separately for the front and rearwvheels. 'Other'than the foregoingand the omission of: the height adjustin or elevation stabilizers at the front" end, the construction'in- Fig.1!) is the sameas in the previoustembodiment. s

With-refyaence-to-Figswl to-G inclusive, it'will .be seenthat a change in elevation o-f either the front or rear'wheels --w-ill produce a force orforces which--will be transmitted :to-and absorbed by the-torsion bar' springs '39. Thus, if the left -frontwheel-28 in-Fig.-3- passes overaloump or upward change in" elevation, the '-torsion -bar- 39 connected -to thelower suspension arm 2 8 will betwisted for angularly de'fiect'ed ina clockwise direction, as viewed in Fig. 3. This torsional deflection of-=the-spring bar will be transmitted directlyto -the =10rwer= end-of the lever arm show-nat'the -'left in? Figs. l -andfi; imparting 1a rotati-vemotionina clockwise rdirection, 'as viewed in these figures, to the lever arm 58. This rotativeor turning effort exerted by the springbar 3910mm the lever a1'm '5iT-will place the link 48in:-

tension and; exert a turnin efiort on' the bell -crank--lever "43. "As; a consequence; ofthis force appliedto the 'bell crank leverp-thereswill :be a --down,ward force applied "to the" wheel atpivot 5.3 of the -bell crank and anupward component-Tat --the-pivot*45of the-bellcrank, this lattercomponent tending 4 to elevate the rear end "of the vehicle. Similarly; the-aetionofthe front suspension arms-2121K}- 28, when r the front? wheel rises .to-passover-achange in" ele-vationgwillbe toexert-'-an*'effort at theinner pivotal' axes of the -suspension arms-tending to"'elevate the front "end-"of-the vehicle. The reverse action-comm above descr'rbed- 'Wil1-take :pla'ce" when 'either the front or rear wheel is I depressed :upon passing over ;a lower change in elevation-during travel -of the vehicle.

- From the foregoing it will be 'seen thatvboth f-ront-and rear-ends of eachatorsion loar xsprin'g -3 9,--in the-embodiment of Figs.-l-to'd inclusive,

ofthe front and rear-wheels. Of'course, itwill -be understood --that --when the front :and rear wheels are-simultaneously elevated; both ends of the vehicle chassisand body will doe iraised' substantially equal distances. When one'frontwheel is elevated and a 'rear'wheel F islowered simul 1'2 taneously, assuming the distances .of elevation :are eq11a1, there will %be substantially :no :change lin rlifti to the vehicle:sprung-weight. 'Itfis important to note-that the "total vertical-force :due to 'achange in elevation of-either'front or-rear wheel-gatsone side of the vehicle is absorbed rby and divided equally; between the front andmiear of the interconnecting torsion bar. Thus, the aavei'agespring'rate of the present spring suspensiorriwill be a-pproximately one-half of the "spring rate-'of a conventionalautomobile. The provisio'nnf the bell crank'levers 43, links .GB and' levers Eiflfat the rearendf of thevehicle enablerthe oppositeends. ofeach :torsion :bar' 39-to '-be":defiected or twisted-in opposite 1 diredtions when; for example; the: front and rear wheelsat correspondingsides- 0f the vehicle are elevated 'or dep'ressed-rat" the same time. Hence; corre- .'sporidi ng upwardior downward'movem'ents of the frontaand -rearzsuspension arms operate to torsionally defiect -theopposite endsgof the torsion ":barsf39dni opposite-directions. I

1 rIt will he? noted im Ffigs. 1 and '10 that- :the uniper suspension arms "or levers 43 are arranged in a common vertical plane somewhat in advance of thelower suspension arms or levers M. ='This :constru'ction =not only "has"the advantage' of' reisisting lateral"twistingiof the rear wheels '2fi lbut -also'rprovides clearance for the driving shafts'for the rear-'wheels;enabling the dr-i-ve to .\betrans- :Iii'itted to th'esewheels'without interference with ther1ev'ers Biland links 48.

'The'embo diment of "the -.'invention illustrated -in :Figsl 12 andi 1-3corresponds substantially to the :embodiment of Figs. 1 to 'lfiinclu'sive, differing --theref rom in that the front end -stabilizer torsion hars 5:32 are extended rearwardly of 'the cross frame niember"-2l and aredrivingly connected "togetherfor loadrcompensatin purposes, thererby enablingfthe 'frontcend of the vehicle to be maintairred atwan' average: riding lheight under "varying-load conditions. In this embodiment :the torsion 'bars 32 are extend-ed: rearwardly :of the -squared portions 32a (which i are anchored to thearms- 2l)--asshown at: 3212 and theends :of -these extensions are i upsetor squared at 32 c and each anchored 'withinia wormrgear I 00 =axially thereon aMeshing with each worm ,gearis-aworm A Ifll fastened to each" end of a: cross shaft --I,B2. :This shaft is rotatably-supportedin any'suitable manner and-in. the present instance is -journalled at. oppositeends;withinthelo wer ends of brackets I03 secured toangle -brackets Hi l I; attached to thesf-rarne-sills -2 (1 and projecting: outwardlytherefrom. The shaft I02 at one side has ansaxial extension drivingly connected to a reversibloieleotrio motor- I 05 carried-by -the' bracket: 104. A5 in the: embodiments of Figs. 7 and- 11 the--pairsof worms and worm gears {I 8.0, l 0 I-v at opposite: ends of -the-shaft I02 are formed, respectively,-= with :right 5 and-rlefthand teeth so that when thevmot'or 1305 isgop'erated in one di rection' or the: othersthe torsionwbars- 3 2" and their extensions 3 2b at .-:oppo 5 site; sides of the" vehicle? will Iibe twisted: crittersional-ly :deflected :in 'opposite directions. zThe compensating motor il 05, as' in 1 theJcaseLof "the :nidtors $6.9; es 3 and-91 ,xiis .automaticallyf. actuated lin 'response' tdchanges in-"static load on the' veihiclerby a delayed action switch mechanism and 13 will-also occurv when the static, load is reduced at the front end of the vehicle. 1 1

As described above, the rear, wheels maybe independently sprungv while' at the same time having provision for load compensation at the rear of the vehicle. Such aconstruction is illustrated in the embodiment of Figs. 14 and 15 wherein the torsion bars 82 in the embodiment -of= Figs. 10 and 11 are dispensed with and coil springs utilized in lieu thereof. In the embodiment ,of Figs. 14 and 15 the rear wheels are independently sprung. As illustrated, each torque arm; 51 carries an inwardly projecting seat I06 for-receiving and confining the lower end of a coil spring II positioned at a rearward inclination, substantially at right angles to the major axis of the torque arm. The upper end of each spring I01 is seated and confined within an extension I 08a of a cross frame member I08 rigidly secured to the cross frame member 22. A conventional telescopic type shock absorber is preferably mounted within the coils of each; spring I01 and interposed between the seats I06 and I08a for the spring. 7 V I. t I 7 Each rear wheel is provided with upper and lower, short and long swinging suspension arms or-links H0 and III which are pivoted at their outer ends at II 2 and H3, respectively, to the upright wheel support or spindle bracket H4. The inner end of each upper suspension arm H0 is pivoted at II5 to a bracket IIB carried by the cross frame member 22, and the inner end of each lower suspension arm III is pivoted-at its inner end at II! to the frame member. The pivotal connections at opposite ends of the suspension arms preferably include yieldable rubber bushings in order to permit a small amount of universal movement during operation of the vehicle. I t 7 Load compensating means is provided for the rear end of the vehicle in the embodiment of Figs. 14 and 15, and this mechanism may take the form illustrated in the embodiment of Figs. 1 to 7 inclusive, differing therefrom in that the rear squared ends 6Ic of the load compensating bars BI are anchored within the inner ends of the lower suspension arms III so that vertical motion of these arms will torsionally deflect the bars BI at the pivotal axes of turning II! of these arms. The operation of the load compensatlng mechanism, as applied to the innerv ends of the suspensionarms III, is the same as previously described.

In the embodiment of Figs. 16 to 21 inclusive I have illustrated various means for operatively connecting the upper suspension arms 43 at the rear of the vehicle with the lever arms which are attached to the rear ends of the torsion bars 39 and; 6| whereby the links 48 are dispensed with. These embodiments, therefore, provide in effecta direct operative connection between each suspension arm 43 and the lever 50 of the embodiment of Fig. 4 with the consequent elimination of the link48.

Referring to Figs. 16 and 17, a lever arm I20 is attached at its lower end to the upset or squared ends 39band Bla of the torsion bars 39 and BI in'the same manner as the lever arm 50 is attached thereto. The lever I20 extends upwardly and, outwardly at a normal angle of approxima ifi y 4 5 andcarries at its outer end a hardened steelsemi-spherical ball I22 slidable within a socket or groove I2Ia in a shoe I2I of bronze or other bearing metal attached to the lower end of a crank arm 43b extending integrally and at approximately an angle of 45? fromthe upper suspension arm 43. It will be understood that the construction shown in Figs. 16 and 1'7 v isprovided at each side of the vehicle at the rear end thereof, and it will be apparent that; upward movement of the wheel will cause the crank arm 43b to impart turning movement to the leyer arm I20 and thereby torsionally twist the bars 39 and fiI. Since these barsare initially twisted, when installed, they will at all timesexert turning effort on the lever arm I20 thereby maintaining the. bearing portions I2I and I22 constantlyin engagement during all operating conditions.

In the embodiment of Figs. 18 and'19' thellever arm. I25, which corresponds to the lever arm I 20, is pressed into channel shape fromsheet steel a n'd is formed at its outerend with a curved pressed semi-spherical ball 'portion I25a slidable within a correspondingly shaped socket or groove I2'4a in a bearing block orshoe I24 rigidly'secured to a reinforcing pla'te" I23 mounted within a channel shaped extension 43c of the suspension arm 43, the latter being pressedfromsheet steel in this instance. 'The' lever arm "I- 25at each side of the vehicle at the rear end thereof is attached at its lower end to the ends 30b and Bla of the torsion bars 39 and. min the sam manner as the'lev'er arms 50 and I20. Theoperation of the modified construction shown in Figs. 18 and 19 is the same as that described above in connection with the embodimentof Figs. 16 and 17. I v

The embodiments of Figs. 20 and 21 are the same as the embodiment of Figs. 16 and 17 with the exception of the operative connection between the crank arm 43b and the lever arm I20. In Fig. 20 this connection takes the form of a resilient or elastic rubber block I26 interposed between the adjacent ends of the crank arm 43b and lever arm I20, this rubber blockbein ulcanized thereto and, hence, yielding to the desired extent during pivotal motion of the suspension arm 43 and lever arm I20 consequent to vertical movement of the rearwheel- In the embodiment of Fig. 21, on the other hand, the operative connection between the adjacent ends of the crank arm 43b and lever arm I20 takes the form of a roller I21 journalled in a bifurcated portion at the upper end of the lever arm I20 and having rolling engagement with a flat hardened bearing surface .on the lower end of the crank arm 43b.

Iclaim: v 1.- In a spring mechanism for a vehicle having pairs of transversely spaced front and rear wheels and a frame, a longitudinal torsion'bar connected to each wheel of one pair and extende ing longitudinally to points intermediate said pairs of wheels, a gear attached to each bar, a transverse shaft supported by the frame intermediate said pairs of wheels drivingly connected to saidgears, and means for turning said shaft to actuate said gears and torsionally deflect said bars thereby to compensate for variations in static load on said frame. v

2.v In a spring mechanism for a vehicle having transversely spaced front and rear wheels, a longitudinal torsion bar connected to eachwheel, a gear attached to each bar, a transverse shaft drivingly connected to each front and rear pair of gears, and means for turning said shafts to actuate said gears and torsionally deflect said bars thereby to compensate for variations in static load on the frame. I v 3. In a spring mechanism for a vehicle having ace-7,610

transverselyspaced front and rear wheels, alongitudinal'torsion'bar connected to each wheel, a gear attached to each bar, a transverse shaft drivingly connected to each front and rear pair of-gears and supported by the frame intermediatesaid front and rear wheels, and separate motor means for independently turning said shafts to actuate said gears and torsionally defleet said bars thereby to compensate for variations in static load on oppositeends of the frame.

4-. In a vehicle having a frame structure and longitudinally spaced pairs of front and rear wheels, a longitudinally extending torsion bar for each wheel, means for-varying the resistance of the torsion bars-for the front wheels independently of the torsion bars for the rear wheels, and means for varying the resistance of the torchanges in elevationwof one e'ndlofthe frame sion bars for the rear wheels independently of the'torsi'on bars for the front wheels, each of said means being automatically responsive to changes i in static load on the frame structure;

' 5. In a spring suspension for a vehicle having a frame and front and rear longitudinally spaced wheels at the same side of the frame, leverarm means connected to eachwheel and also connected'to the frame at longitudinally spaced localities, longitudinal torsional spring means connecting'said'lever arm means and operative thereby totransmit vertical forces in corresponding directionsto the front and rear of the frame in spring means'to'deflect the same and thereby increase or decrease the spring resistance atone 'endof the frame relative to the opposite end of theframe to compensate for varying load conditionsatsaid one end of the frame.

6'. In a spring suspension for a vehicle having aframe and front and rear longitudinallyspaced wheels'at the same side of the frame, lever arm means connected to each wheel andalso connected to the frame at longitudinally spaced localitiealongitudinal torsional spring means connecting' said lever arm means and operative thereby to transmit vertical forces in correspondingdirections to the front and' rear of the frame in' responseto vertical motion of either wheel, torsionalsprin'g means connected to one wheel and operative independent of the other wheel for increasing the spring resistance atone endof the frame relative to the opposite end of the frame thereby to compensate for varyingload conditions at said oneend of the frame, and power operated means operatively connected to said last named springmeans and responsive to "changes in elevation of one end of the frame; relative to the opposite :end of the frame for deflecting 'sa'id secondnamed torsional spring means;

7.- In a spring suspension for avehicle havin a frame and front and rearlongitudinally 'spaced wheels at the same side of the frame, 'lever' arm means connected toeach-wheel means connected to the frame at longitudinally gspace'dflo calit'ies, longitudinal torsional *spi g means conne'ctingsaid lever" arm means and operative thereby to transmit vertical forces in'eorrespondirrg directions t'o the front and rear of 'the frfa-me in"resp'onse to verticalmetionof feither w eel, additional spring 'means conneeted' to one heel for varying the spring resistane'e at one jend -of the frame relative to theopposit'e e dofifthe frame, and means operatively conneeted tosaid lastnamed spring means-and responsive to relative to the oppositeend of th'e frame: for defleeting said last named spring means thereby to compensate for said J relative changes: in :elevation.

8a In a spring'susp'ension for a vehicle having a frame andfront and rearlQngitudinallyspaced wheels at the same side of the frame, lever arm means connected toreachiwheel and also connected to the frame at longitudinally spaced localities, longitudinal torsional spring means connecting said lever arm means and operative thereby to transmit vertical forces incorrespo'n'ding'directions to' the front and rear of the frame in response to vertical motion of either wheel. additional spring means connected to one wheel for varying the'spring resistance at one end of the frame relative to the opposite 'end of the frame, and delayed action power operated means operatively-connected to said last named spring means and responsive to changes in elevation-of one'end of the frame relative to the O posite end of 'theframe for deflecting saidlastnamed spring means to compensate for saidr'elative changes in elevation.

9. In a spring suspension for a vehicle'havin-g a frame and front and rear wh'eelsat a side of the frame, front and rearswinging lever-arm means pivotally connected to the frame and con n'ected to said wheels, longitudinal torsional spring means common to said wheels andconnecting said front and rear lever arm means at the localities of the pivotal connections thereof to the frame and operative by said leverarm means to displace the front and rear of the-frame in corresponding directions upon vertical-motion of a front wheel or a rear wheel, said front and rear lever arm means'including leverarmsyex tending from said pivotal connections in the same directions, torsional spring means connected to one of said wheels adjacent one end of the frame and being independent of the other, and means operativelyconnected to said last named spring means -todeflect the same-thereby to vary the spring resistance at-saidone end of the frame. a

1-0. In a spring *suspensionfor a vehicle-having a frame and front and rear 'wheels' at a side of the frame, front and rear swinging lever arm means. pivotally connected to the frame and connectedlto said wheels; longitud-i nal torsional spring means common to said'wh'eelsand" connecting said front and rear levera;rm"means-at the :localities of therpivotal connections thereof to the. frame and. operative bysaid lever arm means to displace the. front and rear pfthe frame in corresponding directions upon vertical motion of a' front wheel or a-rear wheel, said front and rear lever arm-means--includinglever arms extendirig' from said pivotal connections-in the same directions, torsional spring means-connected to one of said'wheels adjacentone end of the frame and 'being independent of the other and operable to vary the spring resistance-at said one end of the frame, and-poweroper'ated means operatively connected to said last named spring meansand responsive-to relative changes in elevation of Opposite ends" of the frame for deflecting said last named torsional spring means;

11-. In a spring-suspension for a vehicle-having aframe and front and rear wheels-at a side of the frame, front and rear swinging lever arm means pivotallyconnected to the frameand connected to said wheels, longitudinal torsional spring means common to' said wheels and *con hcting said front and rear lever arm means at the localities-ofthe pivotal connections thereof to the frame and operativeby. said lever arm -.means to displace'the frontand rear of the -.frameiin corresponding T directions upon vertical motion of a front wheelor a rear wheel, said front and rear leverflarm means including lever arms extending: fromsaid pivotal-connections in .-.-thez-same directions, additional spring. means connected to one wheel for varying :the spring resistance atone end of the framerelative to the opposite end of the frame, and means operatively connected to ysaid last named spring means :and. responsive to changes in elevation of one endv .ofthe framerelative to the opposite end of. the frame for deflecting said last named spring, means to compensate for. said relative changes inflelevation.

, 12. In a springsuspension, for a vehicle having aframe andpfront and rear wheels at a side of theframe, front andrear swinging lever; arm means pivotallyconnected to'the frame andcon- ,nected to, said wheels, longitudinal torsional -spring means common to; said wheels and con- ,;necting, said front and rear lever arm means at the localities of the pivotal connections thereof -to the,- frameand operative by said lever arm means to-displace, the front and rear of the frame incorresponding directions upon vertical motion of afront .wheel or a" rear .wheel, said 4 front and rear 1ever -arm.means including lever I arms extending from said pivotal connections in the samedirections,- additional spring means connected to each wheel forvarying the spring resistance at each, end of the frame relative to the opposite end of the frame, and meansoper atively connected to eachpf said last named spring means and responsive to changes inelevation of oneend of theframe relative to the opposite end of the frame for independently deflecting each of said last namedspring means to compensate for said relative changes in elevation.

.13. In a spring suspension for a vehicle having a frame and front and rear wheels at a side of the: frame, front and rear swinging lever arm means pivotally connected to the frame and extending from the pivotal connections thereof to the frame in corresponding directions and spring means inopposite directions thereby to ,displace the front and rearof theframe in corresponding vertical directions upon vertical displacement of the front wheel or'the rear wheel, spring means connected to'one wheel and operative independent of theother wheel, and means operatively connected tosaid last namedspring f means and acting thereon to vary the spring resistance at said one wheel.

, :14. In aspring suspension fora vehicle having a frame and front and rear wheels at a side of theframe, front and rear swinging lever arm means pivotally connected to theframe and extending from the pivotal connections thereof to the, framein corresponding directions and connected to said wheels, longitudinal torsional spring means common to the front and rear wheels andlconnected to oneiof said lever arm means for torsional deflection thereof, means for operatively connecting the'other lever arm means to said spring means to-cause said front and rear lever arm means when swinging in corresponding directions to torsionally deflect said spring means in opposite directions thereby to displace the front and rear of the frame in corresponding vertical directions upon vertical displacement of therfront wheel or the rear wheel, spring means connected to one wheel and operative independent of the other wheel for varying the spring, resistance at said one wheel, and power operated means operatively connected to said last named spring means and responsive to changes in elevation of one endof the frame relative to the opposite end of the framedue to variations in static load thereon and acting on I frame.

said last named spring means to deflectv the same thereby to vary the spring resistance atone end of the frame relative to the opposite end of the 15. In a spring suspension for a vehicle having a frame and front and rear- Wheels at a side of the frame, front and rear swinging lever means including lever arms pivotally connected to the frame and extending from the pivotalconnections thereof transversely of the frame. and

,7 connected to said wheels, longitudinal spring means common to the front and rear wheels and connected to said front andrear lever means and effectiveto displace the front and rear of the frame in corresponding vertical directions upon vertical displacement of the front wheel or the rear wheel, additional spring means connected to one wheel and operative independent of the other, and means operatively connected i to and acting on said additionalspring means to deflect the same in response to changes in elevationof one end of the frame relative to the opposite end of the frame thereby to vary the spring resistance at one end of the frame relative nected to one wheel for varying thespring-reto the opposite end. 7 i

l6. In aspring suspension for a vehicle having a frame and front and rear Wheels at a side of the frame, front and rear swinging levermeans I including lever arms pivotally connected togthe frame and extending from the pivotal connections thereof in corresponding directions and connected to said Wheels, longitudinal spring means common to the front and rear wheels and connected to said front and rear lever means and effective'to displace the front and rear of the frame in corresponding vertical directions upon vertical displacement of the front wheel or the rear Wheel, additional spring means consistance at one end of the frame relative to-the opposite end of the frame, and means operative- 1y connected to said last named spring :means' and responsive to changes in elevation of onefiend v of the frame relative to the Opposite endofthe frame for deflecting said lastnamed spring means to compensate for said relative changes in elevation. i

17. In asprin'g suspension for a vehicle having a frame and front and rear wheels at a side of the frame, front and rear swinging lever -means including lever arms pivotally connectedto the frame and extending vfrom the pivotalconnections thereof in corresponding directions and connected to said wheels, longitudinal spring means common to the front and rear wheels'and connected to said front and rear levermeans and effective t displace the front" and rear of the frame in' corresponding vertical directions ti'pon' vertical displacement of the front wheel :or

the-rear wheel, additional spring mean's connected too'ne wheel for varying the spring resistance atone end of the frame relative to the opposite end of the frame, and delayed action power operated means operatively connected to said last named spring means and responsive to changes in elevation of one end of the frame relative to the opposite end of the frame for defie'cting said last named spring means to compensate for said relative changes in elevation.

18. In a spring suspension for a vehicle having a frame and front and rear wheels at a side of the frame, front and rear swinging lever arms pivotally connected to the frame andex- "tending from the pivotal connections thereof transversely of the frame and connected to said wheels, longitudinal torsional spring means common to the front and rear wheels and connected to one of said lever arms for torsional deflection thereby, means including a swinging lever for operativ'ely connecting the other lever arm to said spring means to cause said lever arms when swinging in corresponding directions to torsionally deflect said spring means in opposite directi'ons'ther'eby to displace the front and rear of the frame in corresponding vertical directions upon vertical displacement of the front wheel or -"sa'id-'wheels, longitudinal torsional spring means common to the front and rear wheels and connected to one of said lever arms for torsional deflection thereby, a swinging lever connected tosaid spring means and a link connecting said lever to said other lever arm thereby to cause said lever arms when swinging in corresponding directions to torsionally deflect said spring means in opposite directions thereby to displace the front and rear of the frame in corresponding "vertical directions upon vertical displacement of the front wheel or the rear wheel, additional spring means connected to a wheel, and mechanism operatively connected to said last named "spring means and acting thereon to vary the "spring-"resistance at one end of the frame relative to the opposite end of the frame upon relative changes in elevation of opposite ends of the frame.

' -20. In a vehicle having a frame and front andv rear'wheels, front and rear swinging lever means pivotallyconnected to the frame and connected to said wheels, a spring suspension common to said wheels and extending longitudinally of the frame and connected to said front and rear lever means and operative to displace opposite ends of the frame in corresponding directions upon vertical motion of a front wheel or a rear wheel, and means for levelizing said frame upon rela- "tive chan'ges in elevationof oppositeends thereof "due to changes in static load "on the frame, said last named means comprising compensatingspring means additional to said spring's'uspension for varying "the spring resistance atone ender the frame relative to the oppositeend'or the frameand automatically operatedzmeans :o'pera-tively-connectedilto;saids,compensatingtspring means, and responsive itolchanges in. elevatiomzfof oneliendrofthe-frame; relative. :to. the opposite:;end for -varyi-ng the spring resistance of seiidacompensating spring I means. to compensate for; said relative changes in: elevation. v

. 21. A structure 'as set: forthiingclaim :20. wherein "said :spring'. suspension: comprises .ttorsional 7 spring means and: said; compensating; :Jspring means includes. a atorsion rspring: connected: 'to one of said wheels; "-22. In a vehiclehhaving a frame.;and:two::longitudinally spaced wheels, torsionali springzmeans extending "longitudinally offithe :framexfortyildingly supporting theZframeon-said: wheels, lever arm means connectedto said frame and'ito said spring means adjacent eaoh offsaidfiwheelsrand responsive-to vertical fidisplacement "thereof to deflect said spring means': and thereb'y si'multaneously impart vertical I forces in corresponding directions to opposite end's of the --'frame; -and spring means connected to on'e of said wheels and independent of the other,-and means-aperatively connected to and acting on said last named spring means "to. deflect the same --*and thereby vary the spring-resistanceat one end of the frame relative to the opposite end of the frame totompens'a'te for relative changes in elevation of opposite endsofthe frame.

23. A-s tructureasj-set forth in clai'm'22 where- I i-n -said last n'amedsp'ring means includesa spring torsion bar, said structure including--a3gear attached to said torsion bar, and a reversible electric motor-responsive to a change elevation of one end of the f-rame' for driving saidgear to torsionally deflect said 'torsion bar. I

" 24.- In' a spring suspension for a--=v'ehic-le -having a frame and frontand rear wheels at a side of the frame-front andrear swinging lever aa'rm means pivotally connected to "the frame and con- 'nected to said Wheels; longitudinal torsional spring means common to said wheels and-connecting said front and *rear lever --arm means at the localities of the pivotal *connections 'thereof to the frame and 'operative by said 'leverarm means to displace "the' front andrear of-'--t-he frame in corresponding directions uponvertical motiono f a front wheelfior arear wheel, torsional spring means "connected "to one-"whee1"and*'-independent of the other wheel,- and-powerdriven means 'operatively connected to said-last'nanfed spring means for torsionally deflecting the same thereby to vary the-spring-resistanceat said one wheel relative to the other wheel.

"In a'spring suspensionfor a vehicle having a -frame--and' -front and rear' wheelsat-- a side of the f-rame', front and rearswinging leve'r arm means -cOnnectedto said wheels,-= longitudi- -nal torsional springmeans common to said Wheels and connecting said-front and re'ar levervarm means and operative therebyto displace the frent and rear of *theframe in correspcndi-ng i-r'ections upon vertical displacement "of ither wheel, torsional spring =means-fconnected to one wheel independentlyfl of the other; and me'ans "operatively connected to said lastnam'ed spring means and acting thereon" to 'torsionally deflect the same thereby to vary the spring resistance at said" one wheel.

'26. "A structure asset forth inclaim 2'5--'whe-rein said last named torsional spring "means'has less effective resistance to-wheel displacement thansaid first namedtorsionalspringmeans.

27; In aspring suspension for a vehicle having a frame and front and rear wheels at a side of the frame, front and rear swinging lever arm means pivotally connected to the frame, longitudinal torsional spring means common to the front and rear wheels and connecting said lever arm means at the localities of the pivotal connections thereof to the frame, means for connecting each lever arm means to a wheel, said lever arm means being effective to torsionally deflect said spring means in opposite directions thereby to displace the front and rear of the frame in corresponding vertical directions upon vertical displacement of either wheel, spring means connected to one wheel and independent of the other wheel, and means operatively connected to said last named spring means and acting thereon to deflect the same thereby to vary the spring resistance at said one wheel, said last named spring means having less effective resistance to wheel displacement than said torsional spring means.

28. In a spring suspension for a vehicle having a frame and front and rear wheels at a side of the frame, front and rear swinging lever arm means pivotally connected to the frame and connected to said wheels, longitudinal torsional spring means common to said wheels and connecting said front and rear lever arm means at the localities of the pivotal connections thereof to the frame and operative by said lever arm means to displace the front and rear of the frame in corresponding directions upon vertical motion of a front wheel or a rear wheel, spring means connected to one wheel adjacent one end of the frame and being independent of the other wheel, power operated means for defleeting said last named spring means to vary the spring resistance at one end of the frame to compensate for varying static load conditions, and yieldable means acting against vertical displacement of the wheel at the opposite end of the frame and being independent of said second named spring means for varying the spring rate at said last named wheel.

29. A structure as set forth in claim 20 wherein yieldable means acting against vertical displacement of a front wheel is provided and being independent of said compensating spring means for varying the spring rate at said front wheel, and wherein said compensating spring means is provided for the rear of the frame.

30. In a vehicle having a vehicle structure and front and rear wheels, a spring suspension common to said front and rear wheels and extending therebetween longitudinally of the vehicle structure, separate means operatively connecting said suspension to each wheel and acting on said suspension to effect displacement of opposite ends of the vehicle structure in corresponding directions upon vertical motion of a front wheel or a rear wheel, load compensating spring means connected to one wheel and being independent of the other wheel, power actuated means operative in opposite directions and responsive to a change in elevation of one end of the vehicle structure relative to the opposite end, and means operatively connecting said power actuated means to said load compensating spring means and acting on the latter to deflect the same in 22 one direction or the other thereby to vary the spring resistance at one end of the vehicle structure to compensate for changes in static load thereon.

31. A structure as setforth in claim 30 wherein said spring suspension and said load compensating spring means each includes a torsional spring.

32. A structure as set forth in claim 30 wherein yieldable means acting against vertical displacement of a front wheel is provided and being independent of said compensating spring means for varying the spring rate at said front wheel and wherein said load compensating spring means is provided for the rear wheel.

33. A structure as set forth in claim 30 wherein the means connecting the spring suspension to each wheel includes up and down swinging lever arms pivotally connected to the vehicle structure and connected to said suspension at the localities of the pivotal connections thereof to the vehicle structure.

34. In a vehicle having a vehicle structure and front and rear wheels, a spring suspension common to said front and rear wheels and extending therebetween longitudinally of the vehicle structure, separate means operatively connecting said suspension to each wheel and acting on said suspension to effect displacement of opposite ends of the vehicle structurein corre sponding directions upon vertical motion of a front wheel or a rear wheel, load compensating spring means connected to one wheel, power actuated means responsive to a change in elevation of one end of the vehicle structure relative to the opposite end, and means operatively connecting said power actuated means to said load compensating spring means and acting on the latter to deflect the same thereby to vary the spring resistance at one end of the vehicle structure.

35. A structure as set forth in claim 34 wherein the means operatively connecting said suspension to--one wheel comprises upper and lower swinging lever arms and lever means connected to said suspension and operatively connected to said upper lever arm.

WILLIAM D. ALLISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,396,549 Beatty Nov. 8, 1921 2,075,041 Kliesrath Mar. 30, 1937 2,099,819 Mercier Nov. 23, 1937 2,103,590 Lefevre Dec. 28, 193'? 2,191,211 Krotz Feb. 20, 1940 2,490,311 Rostu Dec. 6, 1949 2,563,261 Montrose-Oster Aug. 7, 1951 FOREIGN PATENTS Number Country Date 86,257 Austria Nov. 10, 1921 182,233 Switzerland Apr. 16, 1936 767,598 France July 20, 1934 828,405 France May 18, 1938 

